// program 10.18
// vararr2d.c -- 使用变长数组的函数
#include <stdio.h>
#define ROWS 3
#define COLS 4
int sum2d(int rows, int cols, int ar[rows][cols]);

int main(void)
{
	int i, j;
	int rs = 3;
	int cs = 10;
	int junk[ROWS][COLS] = {
		{2, 4, 6, 8},
		{3, 5, 7, 9},
		{12, 10, 8, 6}
	};

	int morejunk[ROWS - 1][COLS + 2] = {
		{20, 30, 40, 50, 60, 70},
		{5, 6, 7, 8, 9, 10}
	};

	int varr[rs][cs];		// 变长数组（VLA）
	for (i = 0; i < rs; i++)
	{
		for (j = 0; j < cs; j++)
		{
			varr[i][j] = i * j + j;
		}
	}
	printf("3*4 array\n");
	printf("Sum of all elements = %d\n", sum2d(ROWS, COLS, junk));
	printf("2*6 array\n");
	printf("Sum of all elements = %d\n", sum2d(ROWS -1, COLS + 2, morejunk));
	printf("3*10 VLA\n");
	printf("Sum of all elements = %d\n", sum2d(rs, cs, varr));

	return 0;
}

// 带变长数组形参的函数
int sum2d(int rows, int cols, int ar[rows][cols])
{
	int r;
	int c;
	int tot = 0;

	for (r = 0; r < rows; r++)
	{
		for (c = 0; c < cols; c++)
		{
			tot += ar[r][c];
		}
	}

	return tot;
}
